fix

fix

Find the actual cause. Fix it. Add a regression test. Stop.

Method

1. Reproduce. Get the failing case to a deterministic command line. If you can't reproduce, ask for: exact command, env, input, expected vs actual. Do not guess.
2. Memory pass. mem_search { query: <error or symptom>, k: 5 }. Has this been hit before? Was there a prior fix that regressed?
3. Hypothesis. State the hypothesis explicitly. Cite evidence (line numbers, log lines, behaviour).
4. Verify hypothesis before patching. Add a console.log, run, confirm. If the hypothesis is wrong, restate. Don't patch on a hunch.
5. Smallest fix. One concept change. Target the root cause, not the symptom. If the root cause is in unrelated code, surface that — do not silently expand scope.
6. Regression test. Write a test that fails on the old code and passes on the new. Required.
7. Verify. Full test suite. Lint. Typecheck.

Output shape

Symptom:    <quoted error or behaviour>
Reproduce:  <exact command>
Cause:      <one paragraph, w/ file:line citation>
Fix:        <minimal diff, applied>
Test:       <path to new regression test>
Adjacent:   <any related code that might also be wrong, NOT fixed in this PR>

Rules

• No fix without reproduction.
• No fix without a regression test (rare exception: pure config change with no logic).
• No "while I was here" cleanup. Adjacent issues go to memory + a follow-up suggestion.
• If hypothesis is wrong, restart from step 3. Don't pile patches.
• Never delete or @skip a failing test to make CI green. The test was right.

Anti-patterns

• Patching the symptom (e.g. catch + ignore the exception that signals the bug)
• "Should be fine now" without re-running the failing case
• Refactoring while fixing (separate concerns)
• Adding defensive null checks everywhere when one specific path was wrong

When NOT to use

• Adding a new feature — /siftcoder:add-feature
• Refactoring with same behaviour — /siftcoder:refactor
• Investigation only — /siftcoder:investigate

Subagent dispatch

• investigator agent (if installed) for diagnosis
• Explore for read-only mapping if the bug area is unfamiliar
• general-purpose for the patch + test, with explicit scope file list